Source code for sympy.simplify.traversaltools

"""Tools for applying functions to specified parts of expressions. """

from sympy.core import sympify

[docs]def use(expr, func, level=0, args=(), kwargs={}): """ Use ``func`` to transform ``expr`` at the given level. Examples ======== >>> from sympy import use, expand >>> from sympy.abc import x, y >>> f = (x + y)**2*x + 1 >>> use(f, expand, level=2) x*(x**2 + 2*x*y + y**2) + 1 >>> expand(f) x**3 + 2*x**2*y + x*y**2 + 1 """ def _use(expr, level): if not level: return func(expr, *args, **kwargs) else: if expr.is_Atom: return expr else: level -= 1 _args = [] for arg in expr.args: _args.append(_use(arg, level)) return expr.__class__(*_args) return _use(sympify(expr), level)